CN107001977B

CN107001977B - Cylinder lubricating oil composition for crosshead diesel engine equipped with scrubber

Info

Publication number: CN107001977B
Application number: CN201580062221.4A
Authority: CN
Inventors: 竹岛茂树
Original assignee: JXTG Nippon Oil and Energy Corp
Current assignee: Eneos Corp
Priority date: 2014-11-18
Filing date: 2015-11-18
Publication date: 2021-02-05
Anticipated expiration: 2035-11-18
Also published as: KR20170084105A; EP3222702A4; CN107001977A; SG11201703848XA; US20170321141A1; KR102420190B1; EP3222702A1; EP3222702B1; WO2016080441A1

Abstract

A cylinder lubricating oil composition for a crosshead diesel engine equipped with a scrubber, comprising a base oil and (A) a metal-based detergent, having a base number of 15 to 125mgKOH/g and a kinematic viscosity at 100 ℃ of 10 to 30mm²(ii) s, satisfying the following condition (i) or (ii): (i) contains (B) 0.02 to 5.0 mass% of an anti-emulsifier; (ii) the component (A) contains (A1) Ca phenate detergent and (A2) metal detergent except the Ca phenate detergent, contains (C-1 ') succinimide or its boronized derivative having at least one alkyl or alkenyl group in the molecule at 0.015 mass% or less in terms of nitrogen component, or does not contain the component (C-1'), and the Ph value shown by the following formula (1) is 20X 10^－3The following. Ph value ═ C_Ca×2/(r_MX 40.08) … (1) (formula (1), C_CaRepresents the calcium content (% by mass) from the (A1) component, r_MThe metal ratio of the (A1) component is shown. ).

Description

Cylinder lubricating oil composition for crosshead diesel engine equipped with scrubber

Technical Field

The present invention relates to a cylinder lubricating oil composition for a crosshead diesel engine, and more particularly to a cylinder lubricating oil composition that can be suitably used for a crosshead diesel engine equipped with a scrubber.

Background

Crosshead diesel engines are used in large numbers for the purpose of main engines for large ships. Therefore, it can be said that the portion of the discharged matter from the crosshead diesel engine is large in the influence of the shipping of the ship on the environment.

As concerns the environmental issues, international attention is increasing, and attention is also being paid to nitrogen oxides (NOx) and sulfur oxides (SOx) contained in exhaust gas discharged from ships into the atmosphere. International Maritime Organization (IMO) has determined that Tier III (third limit) for NOx limitation is effective in ECA waters (Emission Control Area) from 2016, and further, studies have been made on SOx limitation to reduce the sulfur content of fuels used in general waters to 0.5% or less from 2020 or 2025.

The application of scrubber technology has attracted attention as a technology for reducing the concentrations of SOx and NOx in exhaust gas of ships. As a technique capable of coping with NOx reduction by IMO Tier III, an EGR (Exhaust Gas Recirculation) scrubber has attracted attention (patent documents 1 to 4). As an option for reducing the SOx emission, in addition to reducing the sulfur content of the fuel (using a low-sulfur fuel), a method may be considered in which the existing high-sulfur fuel is used as it is, but the amount of sulfur oxides discharged by the exhaust gas post-treatment device is made equivalent to that in the case of using a low-sulfur fuel having a sulfur content of 0.5% or less. Since low-sulfur fuel is expensive, the latter method attracts attention, and a method of SOx removal treatment using a scrubber is proposed as an exhaust gas after-treatment device (patent document 5).

A scrubber (dust cleaning and collecting device) generally refers to a device that collects harmful substances (e.g., harmful gas, dust, etc.) in exhaust gas into liquid droplets or a liquid film of an absorbent (e.g., water, etc.) to separate them. For example, a method of absorbing SOx in an aqueous alkali solution such as an aqueous sodium hydroxide solution and separating the absorbed SOx, and collecting coal ash or the like in the aqueous phase and then separating the coal ash or the like by a density difference is conceivable.

In order to efficiently collect the harmful substances in the scrubber, it is necessary to sufficiently contact the gas with the absorbent, and therefore, it is necessary to improve the gas-liquid mixing efficiency of the scrubber. However, the exhaust gas from a diesel engine contains hydrocarbon-based substances such as unburned fuel and lubricating oil mist. Such a hydrocarbon-based substance is insoluble in water, and may be emulsified after vigorously mixing and stirring with water. When these hydrocarbon-based substances are emulsified with water, the coal ash component in the exhaust gas is also included in the emulsion to form scum, and the scum accumulates on the upper part of the absorbent, making separation difficult.

Among engine oils used in diesel engines, a system oil for a crosshead type diesel engine and an engine oil for a 4-stroke plunger type diesel engine are purified by a centrifugal cleaner and then repeatedly used for lubrication. In order to maintain the purifying effect in the centrifugal purifier, these lubricating oils require water separating performance. On the other hand, the cylinder oil for the crosshead diesel engine is a full loss type (Once-through) lubricating oil, and is not purified by a centrifugal purifier and reused, and is not brought into contact with water in the centrifugal purifier. Therefore, the cylinder oil for crosshead diesel engines has not been required to have water separation performance so far.

Documents of the prior art

Patent document

Patent document 1: japanese patent laid-open publication No. 2011-157959

Patent document 2: japanese patent laid-open publication No. 2011-157960

Patent document 3: japanese laid-open patent publication No. 2012 and 137092

Patent document 4: japanese Kohyo publication Hei 8-511074

Patent document 5: japanese patent laid-open publication No. 2011-185275

Disclosure of Invention

Problems to be solved by the invention

The present invention addresses the problem of providing a cylinder lubricating oil composition for a crosshead diesel engine, which is equipped with a scrubber and which can improve the water separation performance and reduce or prevent the formation of scum from a hydrocarbon-based substance, coal ash, and water in the scrubber.

Means for solving the problems

A first aspect of the present invention is a cylinder lubricating oil composition for a crosshead diesel engine equipped with a scrubber, which contains a base oil and (A) a metal-based detergent,

the base number of the composition is 15-125 mgKOH/g, and the kinematic viscosity at 100 ℃ is 10-30 mm²/s，

Satisfies the following condition (i) or (ii):

(i) the lubricating oil composition contains (B) 0.02 to 5.0 mass% of an anti-emulsifier, based on the total amount of the lubricating oil composition;

(ii) the component (A) contains (A1) a Ca phenate detergent and (A2) a metal detergent other than the Ca phenate detergent,

containing not more than 0.015 mass% of (C-1 ') succinimide or boronated derivative thereof having at least one alkyl or alkenyl group in the molecule, based on the total amount of the composition, based on the nitrogen component, or not containing the (C-1') component,

the Ph value shown in the following formula (1) is 20X 10^－3The following.

Ph value ═ C_Ca×2/(r_M×40.08)…(1)

(in the formula (1), C_CaRepresents the calcium content (% by mass) r derived from the above-mentioned component (A1)_MThe metal ratio of the component (A1) is shown. )

In the present specification, the term "crosshead diesel engine equipped with a scrubber" refers to a crosshead diesel engine provided with a mechanism for purifying gas discharged from a cylinder by at least one scrubber. The scrubber may be an EGR scrubber in which the gas having passed through the scrubber is introduced to the intake side of the cylinder (see, for example, patent documents 1 to 4), or may be an exhaust gas scrubber in which the gas having passed through the scrubber is not introduced to the intake side of the cylinder (see, for example, patent document 5). A "crosshead diesel engine" is typically a crosshead 2-stroke diesel engine.

A first embodiment of the first aspect of the present invention is a scrubber-equipped cylinder lubricating oil composition for a crosshead diesel engine, comprising a base oil, (A) a metal-based detergent, and (B) a demulsifier in an amount of 0.02 to 5.0 mass% based on the total amount of the composition, having a base number of 15 to 125mgKOH/g, and having a kinematic viscosity at 100 ℃ of 10 to 30mm²/s。

As a preferred embodiment of the first embodiment, an embodiment containing (C) a nitrogen-containing ashless dispersant can be exemplified.

As a preferred embodiment of the first embodiment, there can be exemplified a mode in which the nitrogen-containing ashless dispersant (C) is contained in an amount of 0.2 mass% or less in terms of nitrogen component based on the total amount of the lubricating oil composition, or a mode in which the nitrogen-containing ashless dispersant (C) is not contained.

As a preferred embodiment of the first embodiment, an embodiment in which the component (B) is 1 or more kinds of polyether compounds can be exemplified. In this embodiment, the number average molecular weight of the component (B) is preferably 500 or more. In the present invention, the "polyether compound" refers to a compound having a polyether moiety, and the polyether moiety may be further modified by, for example, an ester bond.

As a preferred embodiment of the first embodiment, an embodiment in which the component (a) is Ca phenolate can be exemplified.

A second embodiment of the first embodiment of the present invention is a scrubber-equipped cylinder lubricating oil composition for a crosshead diesel engine, which contains a base oil, (A1) a Ca phenate detergent, and (A2) a metal detergent other than the Ca phenate detergent,

containing 0.015 mass% or less of (C-1) succinimide having at least one alkyl or alkenyl group in the molecule or a boronated derivative thereof based on the total amount of the composition, based on the nitrogen component, or not containing the (C-1) component,

the base number is 15 to 125mgKOH/g,

the kinematic viscosity at 100 ℃ is 10-30 mm²/s，

The Ph value shown in the following formula (1) is 20X 10^－3The following.

Ph value ═ C_Ca×2/(r_M×40.08)…(1)

(in the formula (1), C_CaRepresents the calcium content (% by mass based on the total amount of the composition) of the component (A1)_MThe metal ratio of the (A1) component is shown. )

As a preferred embodiment of the second embodiment, there can be exemplified a method in which (C) succinimide having at least one alkyl group or alkenyl group in the molecule or a boronated derivative thereof is contained in an amount of more than 0 mass% and 0.015 mass% or less in terms of nitrogen component based on the total amount of the composition.

As a preferred embodiment of the second embodiment, an embodiment in which the component (a2) is a Ca sulfonate and/or a Ca salicylate can be exemplified.

A second aspect of the present invention is a cylinder lubrication method for a crosshead diesel engine equipped with a scrubber, including:

a step of operating a crosshead diesel engine equipped with a scrubber while supplying the cylinder lubricating oil composition for the crosshead diesel engine equipped with the scrubber according to the first aspect of the invention to a cylinder of the crosshead diesel engine equipped with the scrubber; and

a step of purifying at least a part of the gas discharged from the cylinder in a scrubber.

In the second aspect of the present invention, the step of purging in the scrubber preferably includes a step of bringing the gas introduced into the scrubber into contact with water and/or an alkaline aqueous solution.

Effects of the invention

According to the first aspect of the present invention, there can be provided a cylinder oil for a crosshead diesel engine, which is equipped with a scrubber and which can reduce or suppress the generation of scum from a hydrocarbon-based substance, coal ash, and moisture in the scrubber.

According to the method for lubricating a cylinder of a crosshead diesel engine equipped with a scrubber according to the second aspect of the present invention, when gas discharged from the cylinder is cleaned in the scrubber, the generation of scum from hydrocarbon-based substances, soot, and moisture in the scrubber can be reduced or suppressed.

Detailed Description

The present invention will be described in detail below. Unless otherwise specified, "a to B" for numerical values a and B means "a to B inclusive". In the case where only the value B is associated with a unit in this expression, the unit also applies to the value a. In addition, "or" and "or" mean logical or unless otherwise specified.

< lubricating base oil >

As the base oil in the present invention, at least one selected from mineral oils and synthetic oils can be used.

The mineral oil is not particularly limited, and is preferably exemplified by: desulfurizing and hydrogenolyzing atmospheric residue obtained by atmospheric distillation of crude oil, and fractionating the residue into oil of a desired viscosity grade; an oil obtained by subjecting the above atmospheric residue to solvent dewaxing or contact dewaxing, and further solvent extraction and hydrogenation as required.

In addition, as mineral oils, there can be used: further distilling the atmospheric distillation residue under reduced pressure to fractionate the residue into a desired viscosity grade, and then subjecting the residue to solvent dewaxing by a process such as solvent refining and hydrorefining to produce a petroleum wax isomerized lubricant base oil by hydroisomerizing a petroleum wax byproduct produced in the dewaxing step in the base oil production step; or GTL WAX isomerization lubricant base oil produced by a method of isomerizing GTL WAX (gas to liquid WAX) produced by a fischer-tropsch process or the like. The basic manufacturing process for producing these wax-isomerized lubricant base oils is the same as the process for producing the hydrogenolysis base oil.

Further, the synthetic oil is not particularly limited, and a synthetic oil generally used as a lubricant base oil can be used. Specific examples thereof include: polybutene and its hydrides; polyalphaolefins and hydrides thereof, such as oligomers of 1-octene, 1-decene, dodecene, etc., or mixtures thereof; diesters such as ditridecyl glutarate, di-2-ethylhexyl adipate, diisodecyl adipate, ditridecyl adipate and di-2-ethylhexyl sebacate; polyhydric alcohol esters such as trimethylolpropane caprylate, trimethylolpropane pelargonate, pentaerythritol-2-ethylhexanoate, pentaerythritol pelargonate and the like; copolymers of dicarboxylic acids such as dibutyl maleate and alpha-olefins having 2 to 30 carbon atoms; aromatic synthetic oils such as alkylnaphthalene, alkylbenzene, and aromatic ester; and mixtures thereof, and the like.

The kinematic viscosity of the base oil at 100 ℃ is preferably 10mm²At least s, more preferably 14mm²More than s, preferably 25mm²Less than s, more preferably 20mm²The ratio of the water to the water is less than s. When the kinematic viscosity of the base oil at 100 ℃ is not less than the lower limit value, a sufficient oil film can be formed on the lubricated part, and good lubricity can be obtained. Further, by setting the kinematic viscosity at 100 ℃ of the base oil to the upper limit value or less, good fluidity at low temperature can be obtained. In the present invention, the kinematic viscosity at 100 ℃ means the kinematic viscosity at 100 ℃ specified in ASTM D-445.

As a preferred embodiment of the base oil, a kinematic viscosity at 100 ℃ of 10 to 14mm can be exemplified²The base oil/s has a kinematic viscosity of 20-40 mm at 100 DEG C²A mixed base oil of base oil/s.

The viscosity index of the base oil is preferably 85 or more, more preferably 90 or more, and particularly preferably 95 or more. By setting the viscosity index of the base oil to be equal to or higher than the lower limit value, the viscosity at low temperature can be suppressed to a low level, and good startability can be obtained. Here, in the present invention, the viscosity index means a viscosity index measured in accordance with JIS K2283-1993.

The saturated component content of the base oil based on the total amount of the base oil is preferably 50% by mass or more, more preferably 55% by mass or more, and further preferably 90% by mass or less, more preferably 75% by mass or less. By setting the saturated component to the lower limit or more, good oxidation stability can be obtained. In addition, when the saturated component is not more than the above upper limit, sufficient solubility of asphaltenes and deteriorated substances can be obtained, and thus good purification performance can be obtained. In the present specification, the saturated component means a saturated component measured by the method described in ASTM D2007-93.

Metal-based detergent (1) < (A)

In the first embodiment of the lubricating oil composition of the present invention, the metal-based detergent (a) (hereinafter referred to as "component (a)") is a so-called metal-based detergent which is generally used in lubricating oils. Examples of the component (a) include phenate detergents, sulfonate detergents and salicylate detergents. These metal-based detergents may be used alone or in combination of 2 or more.

As the component (a), a phenol salt-based detergent is particularly preferably used.

As the phenate-based detergent, an alkaline earth metal salt of a compound having a structure represented by the following formula (1), or an alkaline salt thereof, or an overbased salt (oversalts) is preferably exemplified. Examples of the alkaline earth metal include magnesium, barium and calcium, and among these, magnesium or calcium is preferable, and calcium is particularly preferable. Further, 1 kind of the component (A) may be used alone, or 2 or more kinds may be used in combination.

In the formula (1), R¹Represents a linear or branched, saturated or unsaturated alkyl or alkenyl group having 6 to 21 carbon atoms, m is a polymerization degree and represents an integer of 1 to 10, A represents a thioether (-S-) group or a methylene (-CH)₂-) group, x represents an integer of 1 to 3. In addition, R¹Combinations of more than 2 different groups are also possible.

R in the formula (1)¹The number of carbon atoms of (A) is preferably 9 to 18, more preferably 9 to 15. R¹May result in poor solubility for the base oil when the number of carbon atoms of (A) is less than 6, while at R¹When the number of carbon atoms of (2) exceeds 21, the production may be difficult and the heat resistance may be deteriorated.

The polymerization degree m in the formula (1) is preferably 1 to 4. When the polymerization degree m is within this range, the heat resistance can be improved.

The base number of the phenolic salt-based detergent is preferably 60mgKOH/g or more, more preferably 100mgKOH/g or more, further preferably 350mgKOH/g or less, and further preferably 300mgKOH/g or less. When the base number is not less than the lower limit, good acid-neutralizing performance can be obtained, and when the base number is not more than the upper limit, good purification performance can be obtained. Herein, the base number in the present invention means a base number measured by a perchloric acid method.

The sulfonate-based detergent is preferably an alkaline earth metal salt of an alkyl aromatic sulfonic acid obtained by sulfonating an alkyl aromatic compound, or a basic salt or a highly basic salt thereof. The alkyl aromatic compound preferably has a weight average molecular weight of 400 to 1500, more preferably 700 to 1300.

Examples of the alkaline earth metal include magnesium, barium and calcium, preferably magnesium or calcium, and particularly preferably calcium. Examples of the alkyl aromatic sulfonic acid include so-called petroleum sulfonic acid and synthetic sulfonic acid. Examples of the petroleum sulfonic acid include those obtained by sulfonating an alkyl aromatic compound in a lubricating oil fraction of mineral oil, and so-called mahogany acid which is a by-product in the production of white oil. Examples of the synthetic sulfonic acid include a by-product in an alkylbenzene production facility recovered as a raw material of a detergent, and a product obtained by sulfonating an alkylbenzene having a linear or branched alkyl group obtained by alkylating benzene with a polyolefin. Another example of the synthetic sulfonic acid is one obtained by sulfonating alkylnaphthalene such as dinonylnaphthalene. The sulfonating agent used in sulfonating these alkyl aromatic compounds is not particularly limited, and fuming sulfuric acid or sulfuric anhydride, for example, can be used.

The base number of the sulfonate-based detergent is preferably not less than 10mgKOH/g, more preferably not less than 150mgKOH/g, still more preferably not less than 250mgKOH/g, and further preferably not more than 500mgKOH/g, more preferably not more than 450 mgKOH/g. When the base number is not less than the lower limit, good acid-neutralizing performance can be obtained, and when the base number is not more than the upper limit, good purification performance can be obtained.

The salicylate-based detergent is preferably a metal salicylate, an alkali salt thereof, or an overbased salt thereof. The metal salicylate mentioned here is a compound represented by the following formula (2).

In the above formula (2), R²Each independently represents an alkyl group or alkenyl group having 14 to 30 carbon atoms, M represents an alkaline earth metal, and n represents 1 or 2. As M, calcium or magnesium is preferred, and calcium is particularly preferred. As n, 1 is preferable. When n is 2, R²Combinations of different groups are possible.

A preferred embodiment of the salicylate-based detergent includes an alkaline earth metal salicylate having n ═ 1 in the formula (2), an alkaline salt thereof, or an overbased salt thereof.

The method for producing the alkaline earth metal salicylate is not particularly limited, and a known method for producing monoalkyl salicylate can be used. For example, alkaline earth metal salicylates can be obtained by reacting a metal base such as an oxide or hydroxide of an alkaline earth metal with monoalkylsalicylic acid obtained by alkylating phenol as a starting material with an olefin and then carboxylating the alkylated monoalkylsalicylic acid with carbon dioxide gas or the like, or by alkylating salicylic acid with an equivalent amount of the above-mentioned olefin as a starting material, or by once converting the monoalkylsalicylic acid or the like into an alkali metal salt such as a sodium salt or a potassium salt and then metal-exchanging the alkali metal salt with the alkaline earth metal salt.

The method for obtaining the basic salt of the alkaline earth metal salicylate is not particularly limited, and for example, the basic salt can be obtained by heating the alkaline earth metal salicylate with an excess amount of alkaline earth metal salt or alkaline earth metal base (hydroxide or oxide of alkaline earth metal) in the presence of water.

The method for obtaining the overbased salt of the alkaline earth metal salicylate is not particularly limited, and for example, the overbased salt can be obtained by reacting an alkaline earth metal salicylate with a base such as a hydroxide of an alkaline earth metal in the presence of carbon dioxide gas or boric acid or a borate.

The base number of the salicylate-based detergent is preferably 60mgKOH/g or more, more preferably 100mgKOH/g or more, further preferably 350mgKOH/g or less, more preferably 300mgKOH/g or less. By setting the base number to the lower limit or more, good acid-neutralizing performance can be obtained, and by setting the base number to the upper limit or less, good purification performance can be obtained.

In the first embodiment of the lubricating oil composition of the present invention, it is preferable to use 1 or more calcium detergents selected from Ca phenate detergents, Ca sulfonate detergents and Ca salicylate detergents as the component (a).

The Ca phenate-based detergent is a detergent using calcium as an alkaline earth metal among the above-mentioned phenate-based detergents. That is, it means a calcium salt of alkylphenol sulfide (alkylphenol sulfoide), a basic salt thereof, or an overbased salt thereof.

The Ca sulfonate-based detergent is a detergent using calcium as an alkaline earth metal among the above sulfonate-based detergents. That is, it means a calcium salt of an alkyl aromatic sulfonic acid, a basic salt thereof, or an overbased salt thereof.

The Ca salicylate-based detergent is a detergent in which calcium is used as a metal in the above salicylate-based detergent. That is, it means calcium salicylate or its basic salt, or overbased salt.

When a calcium detergent is used as the component (a), the content thereof is preferably 0.50 to 4.3% by mass of the total amount of the lubricating oil composition, based on the calcium component.

Metal-based detergent (2) < (A)

In the second embodiment of the lubricating oil composition of the present invention, component (a) contains (a1) a Ca phenate detergent and (a2) a metal detergent other than the Ca phenate detergent.

((A1) Ca phenate based detergent

Examples of the Ca phenolate detergent (a1) (hereinafter referred to as "component (a 1)") include calcium salts of compounds having the structure represented by the above formula (1), basic salts thereof, and overbased salts thereof. (A1) The components may be used alone in 1 kind, or 2 or more kinds may be used in combination. (A1) Preferred embodiments of the component (a) are as described above for the phenate-based detergent.

((A2) Ca phenate detergent other than Metal detergent

(A2) The metal-based detergent other than the Ca phenate-based detergent (hereinafter referred to as "component a 2") is preferably a metal-based detergent other than a phenate-based detergent, and examples of such metal-based detergents include sulfonate-based detergents and salicylate-based detergents. These metal-based detergents may be used alone or in combination of 2 or more.

The sulfonate-based detergent described above can be used as the sulfonate-based detergent. Preferred embodiments of the sulfonate-based detergent are as described above.

The salicylate-based detergent described above can be used as the salicylate-based detergent. The preferred mode of the salicylate-based detergent is as described above.

In a preferred embodiment, the component (a2) is a Ca sulfonate-based detergent and/or a Ca salicylate-based detergent.

The base number of the Ca sulfonate-based detergent is preferably not less than 10mgKOH/g, more preferably not less than 150mgKOH/g, still more preferably not less than 250mgKOH/g, and further preferably not more than 500mgKOH/g, more preferably not more than 450 mgKOH/g. By setting the base number to the lower limit or more, good acid-neutralizing performance can be obtained, and by setting the base number to the upper limit or less, good purification performance can be obtained.

The base number of the Ca salicylate-based detergent is preferably 60mgKOH/g or more, more preferably 100mgKOH/g or more, further preferably 350mgKOH/g or less, and further preferably 300 mgKOH/g. By setting the base number to the lower limit or more, good acid-neutralizing performance can be obtained, and by setting the base number to the upper limit or less, good purification performance can be obtained.

(B) anti-emulsifier

As the (B) demulsifier (hereinafter referred to as the "(B) component") in the first embodiment of the lubricating oil composition of the present invention, a so-called demulsifier which is commercially available can be used without particular limitation, and among them, a polyether compound is preferably used.

As the polyether compound which can be preferably used as the component (B), there can be mentioned: polypropylene glycol monoalkyl ethers such as polypropylene glycol butyl ether and polypropylene glycol stearyl ether; polyoxyethylene polyoxypropylene alkyl ether (oxyethylene-oxypropylene copolymer); polyoxyethylene alkyl ethers; polyethylene glycol fatty acid esters; polyoxyethylene glycerin fatty acid ester; polyoxyethylene sorbitol fatty acid esters; and polyoxyethylene sorbitan fatty acid ester, and 1 or more polyether compounds selected from these can be used alone or in combination.

Among these polyether compounds, polyether compounds containing oxypropylene units such as polypropylene glycol butyl ether, polypropylene glycol stearyl ether and other polyoxypropylene monoalkyl ethers, polyoxyethylene polyoxypropylene alkyl ethers (oxyethylene-oxypropylene copolymers) and the like are particularly preferable.

(B) The molecular weight of the component (b) is not particularly limited, but the number average molecular weight is preferably 350 or more, more preferably 500 or more, further preferably 1000 or more, and further preferably 30000 or less, more preferably 10000 or less, further preferably 5000 or less. When the number average molecular weight of the component (B) is not less than the lower limit, good anti-emulsification properties can be obtained.

(B) The HLB (hydrophilic-lipophilic balance) value of the component is not particularly limited as long as it can exhibit an anti-emulsification effect (emulsion destabilization effect), and is preferably 13 or more, and more preferably 14.5 or more. The HLB value is, by definition, necessarily 20 or less, and is preferably 19.5 or less from the viewpoint of affinity with the base oil.

The content of the component (B) in the first embodiment of the lubricating oil composition of the present invention is 0.02 to 5% by mass, preferably 0.03% by mass or more, more preferably 0.04% by mass or more, and preferably 4% by mass or less, more preferably 3% by mass or less, based on the total amount of the lubricating oil composition. When the content of component (B) is not less than the lower limit, good emulsion resistance can be obtained.

Nitrogen-containing ashless dispersant (1) < (C)

The lubricating oil composition of the present invention may contain (C) a nitrogen-containing ashless dispersant (hereinafter referred to as "component (C)").

As component (C), for example, 1 or more compounds selected from the following (C-1) to (C-3) can be used.

(C-1) a succinimide having at least one alkyl group or alkenyl group in the molecule or a derivative thereof (hereinafter referred to as "component (C-1)"),

(C-2) benzylamine having at least 1 alkyl group or alkenyl group in the molecule or a derivative thereof (hereinafter referred to as "component (C-2)"),

(C-3) a polyamine having at least 1 alkyl group or alkenyl group in the molecule or a derivative thereof (hereinafter referred to as "component (C-3)").

The component (C) is particularly preferably the component (C-1).

Examples of the succinimide having at least one alkyl group or alkenyl group in the molecule in the component (C-1) include compounds represented by the following formula (3) or (4).

In the formula (3), R³Represents an alkyl group or alkenyl group having 40 to 400 carbon atoms, and h represents an integer of 1 to 5, preferably 2 to 4. R³The number of carbon atoms of (b) is preferably 60 or more, and more preferably 350 or less.

In the formula (4), R⁴Each independently represents an alkyl group or an alkenyl group having 40 to 400 carbon atoms, or a combination of different groups. R⁴Particularly preferred is a polybutenyl group. In addition, i represents an integer of 0 to 4, preferably 1 to 3. R⁴The number of carbon atoms of (b) is preferably 60 or more, and more preferably 350 or less.

By using R in the formula (3) and the formula (4)³、R⁴The number of carbon atoms of (a) is not less than the above lower limit, and good solubility in the lubricant base oil can be obtained. On the other hand, by making R³、R⁴The number of carbon atoms of (b) is not more than the above upper limit, and the low temperature fluidity of the lubricating oil composition can be improved.

Alkyl or alkenyl (R) in the formulae (3) and (4)³、R⁴) May be linear or branched, and is preferably represented byAn oligomer of an olefin such as propylene, 1-butene or isobutylene, or a branched alkyl group or a branched alkenyl group derived from a co-oligomer of ethylene and propylene. Among them, branched alkyl or alkenyl groups derived from an isobutylene oligomer called polyisobutylene, or polybutenyl groups are most preferable for habituation.

Alkyl or alkenyl (R) in the formulae (3) and (4)³、R⁴) The weight average molecular weight of the resin is preferably 800 to 3500.

The succinimide having at least 1 alkyl group or alkenyl group in the molecule includes: a so-called mono-type succinimide represented by formula (3) in which succinic anhydride is added to only one end of a polyamine chain, and a so-called di-type succinimide represented by formula (4) in which succinic anhydride is added to both ends of a polyamine chain. The lubricating oil composition of the present invention may contain either of a mono-type succinimide and a di-type succinimide, or may contain a mixture of both.

The method for producing a succinimide having at least 1 alkyl group or alkenyl group in the molecule is not particularly limited, and for example, it can be obtained by reacting a compound having an alkyl group or alkenyl group having 40 to 400 carbon atoms with maleic anhydride at 100 to 200 ℃ to obtain alkyl succinic acid or alkenyl succinic acid, and reacting the alkyl succinic acid or alkenyl succinic acid with polyamine. Examples of the polyamine include diethylenetriamine, triethylenetetramine, tetraethylenepentamine, and pentaethylenehexamine.

As the benzylamine having at least 1 alkyl group or alkenyl group in the molecule in the component (C-2), a compound represented by the following formula (5) can be exemplified.

In the formula (5), R⁵Represents an alkyl group or alkenyl group having 40 to 400 carbon atoms, and j represents an integer of 1 to 5, preferably 2 to 4. R⁵The number of carbon atoms of (b) is preferably 60 or more, and more preferably 350 or less.

The method for producing the component (C-2) is not particularly limited. Examples thereof include: a method in which a polyolefin such as a propylene oligomer, polybutene, or an ethylene- α -olefin copolymer is reacted with phenol to produce an alkylphenol, and then formaldehyde is reacted with a polyamine such as diethylenetriamine, triethylenetetramine, tetraethylenepentamine, or pentaethylenehexamine by a mannich reaction.

As the polyamine having at least 1 alkyl group or alkenyl group in the molecule in the component (C-3), a compound represented by the following formula (7) can be exemplified.

R⁶-NH-(CH₂CH₂NH)_k-H(6)

In the formula (6), R⁶Represents an alkyl group or alkenyl group having 40 to 400 carbon atoms or less, and k represents an integer of 1 to 5, preferably 2 to 4. R⁶The number of carbon atoms of (b) is preferably 60 or more, and more preferably 350 or less.

The method for producing the component (C-3) is not particularly limited. For example, a method of chlorinating a polyolefin such as a propylene oligomer, polybutene or an ethylene- α -olefin copolymer, and then reacting the chlorinated polyolefin with ammonia or a polyamine such as ethylenediamine, diethylenetriamine, triethylenetetramine, tetraethylenepentamine or pentaethylenehexamine is exemplified.

Examples of the derivatives of the components (C-1) to (C-3) include: (i) a modified compound using an oxygen-containing organic compound, wherein the above succinimide, benzylamine, or polyamine having at least 1 alkyl group or alkenyl group in the molecule (hereinafter referred to as "the above nitrogen-containing compound") is reacted with a monocarboxylic acid having 1 to 30 carbon atoms such as a fatty acid, a polycarboxylic acid having 2 to 30 carbon atoms (for example, oxalic acid, phthalic acid, trimellitic acid, pyromellitic acid, or the like), an acid anhydride or ester compound thereof, an oxyalkylene group having 2 to 6 carbon atoms, or a hydroxy (poly) oxyalkylene carbonate, so that a part or all of the remaining amino groups and/or imino groups are neutralized or amidated; (ii) a boron-modified compound in which a part or all of the remaining amino groups and/or imino groups are neutralized or amidated by reacting the above-mentioned nitrogen-containing compound with boric acid; (iii) a phosphoric acid-modified compound in which a part or all of the remaining amino groups and/or imino groups are neutralized or amidated by reacting the above-mentioned nitrogen-containing compound with phosphoric acid; (iv) a sulfur-modified compound obtained by reacting the above-mentioned nitrogen-containing compound with a sulfur compound; and (v) a modified compound obtained by modifying the combination of the above-mentioned nitrogen-containing compounds with at least 2 kinds of modifications selected from the group consisting of modification with an oxygen-containing organic compound, boron modification, phosphoric acid modification, and sulfur modification. Among the derivatives (i) to (v), the use of a boric acid-modified compound of alkenyl succinimide, particularly a boric acid-modified compound of a bis-type alkenyl succinimide, can further improve the heat resistance of the lubricating oil composition.

The molecular weight of the component (C) is not particularly limited, and a suitable weight average molecular weight is 1000 to 8000.

In the first embodiment of the lubricating oil composition of the present invention, the content of the component (C) is preferably 0.02 mass% or more, more preferably 0.04 mass% or more, further preferably 0.07 mass% or more, and further preferably 0.2 mass% or less, and more preferably 0.12 mass% or less, in terms of nitrogen component, based on the total amount of the lubricating oil composition. (C) By setting the content of the component to the lower limit or more, the scorch resistance (heat resistance) of the lubricating oil composition can be sufficiently improved. Further, by setting the content of component (C) to the upper limit or less, it is possible to obtain a good separation performance of impurities in the centrifugal cleaner, and it is possible to improve the water separation performance and to easily suppress the generation of scum in the scrubber.

(C) Nitrogen-containing ashless dispersant (2)

In the second embodiment of the lubricating oil composition of the present invention, a succinimide or a boronated derivative thereof having at least one alkyl or alkenyl group in the molecule (C-1 ') may or may not be contained (hereinafter referred to as the "component C-1'). When the lubricating oil composition of the second embodiment of the present invention contains the component (C-1 '), the content of the component (C-1') must be 0.015 mass% or less in terms of nitrogen component based on the total amount of the composition. By setting the content of the component (C-1') to 0.015 mass% or less in terms of nitrogen, good anti-emulsification properties can be obtained, and the generation of scum in the scrubber can be suppressed.

Examples of the succinimide having at least one alkyl group or alkenyl group in the molecule include compounds represented by the above formula (3) or (4) described above for the component (C-1) in the first embodiment. Preferred modes for these compounds are as described above.

Examples of the boronated derivative of succinimide having at least 1 alkyl group or alkenyl group in the molecule include the so-called boron-modified compounds described above in which succinimide having at least 1 alkyl group or alkenyl group in the molecule is allowed to act on boric acid, thereby neutralizing or amidating a part or all of the remaining amino groups and/or imino groups.

The molecular weight of the component (C-1') is not particularly limited, and a suitable weight average molecular weight is 1000 to 8000.

< other additives >

The lubricating oil composition of the present invention may further contain any additives commonly used in lubricating oils, depending on the purpose. Examples of such additives include zinc dithiophosphate, antioxidants, antifoaming agents, pour point depressants, metal deactivators, and extreme pressure agents.

As the zinc dithiophosphate (ZnDTP), a compound represented by the following formula (5) is preferably used.

In the formula (7), R⁷Each independently represents a hydrocarbon group having 1 to 24 carbon atoms, or a combination of different groups. The hydrocarbon group having 1 to 24 carbon atoms preferably includes a linear or branched alkyl group having 1 to 24 carbon atoms. In addition, R⁷The number of carbon atoms of (b) is preferably 3 or more, more preferably 12 or less, and still more preferably 8 or less. In addition, as R⁷The alkyl group of (a) may be any of primary, secondary and tertiary alkyl groups, preferably primary or secondary alkyl groups, or mixtures thereof, most preferably primary alkyl groups.

Examples of the zinc dithiophosphate (ZnDTP) include zinc dialkyldithiophosphates having a linear or branched (primary, secondary or tertiary, preferably primary or secondary) alkyl group having 3 to 18 carbon atoms, preferably 3 to 10 carbon atoms, such as zinc dipropyldithiophosphate, zinc dibutyldithiophosphate, zinc dipentyldithiophosphate, zinc dihexyldithiophosphate, zinc diheptyldithiophosphate, and zinc dioctyldithiophosphate; zinc di ((alkyl) aryl) dithiophosphates having an aryl or alkylaryl group having 6 to 18 carbon atoms, preferably 6 to 10 carbon atoms, such as zinc diphenyl dithiophosphate or zinc ditolyl dithiophosphate; and mixtures of 2 or more of them.

The method for producing the zinc dithiophosphate is not particularly limited. For example, by making the carrier have a length corresponding to R⁷The alcohol of (2) is reacted with phosphorus pentasulfide to synthesize dithiophosphoric acid, which is neutralized with zinc oxide.

In the lubricating oil composition of the present invention, the content of the zinc dithiophosphate is preferably 0.03 to 1.0 mass%, more preferably 0.05 to 0.5 mass%, and particularly preferably 0.01 to 0.3 mass%, based on the total amount of the composition. The zinc dithiophosphate is preferably contained in an amount such that the phosphorus component in the lubricating oil composition is 25 to 700 mass ppm, and desirably such that the phosphorus component in the lubricating oil composition is more preferably 40 mass ppm or more, still more preferably 50 mass ppm or more, particularly preferably 80 mass ppm or more, and preferably 500 mass ppm or less, still more preferably 300 mass ppm or less, and particularly preferably 250 mass ppm or less. When the phosphorus content derived from zinc dithiophosphate in the lubricating oil composition is 25 mass ppm or more, the required oxidation stability can be ensured, and when the phosphorus content is 700 mass ppm or less, the decrease in base number due to hydrolysis of zinc dithiophosphate can be avoided.

Examples of the antioxidant include ashless antioxidants such as phenol antioxidants and amine antioxidants, and metal antioxidants. Among them, a phenol-based antioxidant and/or an amine-based antioxidant is preferably used from the viewpoint of maintaining the high-temperature purification performance. When the lubricating oil composition of the present invention contains an antioxidant, the content thereof is preferably 0.05% by mass or more, more preferably 0.1% by mass or more, particularly preferably 0.3% by mass or more in the case of an amine-based antioxidant, and particularly preferably 0.15% by mass or more in the case of a phenol-based antioxidant, based on the total amount of the composition. The upper limit of the content of the antioxidant is not particularly limited, but is preferably 5% by mass or less, and more preferably 2% by mass or less, based on the total amount of the composition.

Examples of the defoaming agent include silicone oil, alkenyl succinic acid derivatives, esters of polyhydroxyaliphatic alcohols and long-chain fatty acids, methyl salicylate and ortho-hydroxybenzyl alcohol, aluminum stearate, potassium oleate, N-dialkyl-allylamine nitroaminoalkanols, aromatic amine salts of isopentyl octyl phosphate, alkylalkylene diphosphate, metal derivatives of thioether, metal derivatives of disulfide, fluorine compounds of aliphatic hydrocarbons, triethylsilane, dichlorosilane, alkylphenyl polyglycol ether sulfur, fluoroalkyl ethers, and the like. When the lubricating oil composition of the present invention contains an antifoaming agent, the content thereof is usually 0.0005 to 1 mass% based on the total amount of the composition, and when the antifoaming agent contains silicon, the Si component in the lubricating oil composition is preferably 5 to 50 mass ppm.

Examples of the pour point depressant include polymethacrylate-based polymers that match the lubricant base oil used. When the pour point depressant is contained in the lubricating oil composition of the present invention, the content thereof is usually 0.005 to 5% by mass based on the total amount of the composition.

Examples of the metal deactivator include imidazoline, pyrimidine derivatives, alkylthiadiazoles, mercaptobenzothiazoles, benzotriazoles or derivatives thereof, 1,3, 4-thiadiazole polysulfide, 1,3, 4-thiadiazolyl-2, 5-dialkyldithiocarbamate, 2- (alkyldithio) benzimidazole, and β - (ortho-carboxybenzylthio) propionitrile. When the lubricating oil composition of the present invention contains a metal deactivator, the content thereof is usually 0.005 to 1% by mass based on the total amount of the composition.

As the extreme pressure agent, for example, a sulfur-based, phosphorus-based, sulfur-phosphorus-based extreme pressure agent or the like can be used. Specific examples thereof include phosphites, thiophosphites, dithiophosphates, trithiophosphites, phosphates, thiophosphates, dithiophosphates, trithiophosphates, amine salts thereof, metal salts thereof, derivatives thereof, dithiocarbamates, zinc dithiocarbamates, molybdenum dithiocarbamates, disulfides, polysulfides, olefin sulfides, and oil and fat sulfides. When the lubricating oil composition of the present invention contains an extreme pressure agent, the content thereof is not particularly limited, and is usually 0.01 to 5% by mass based on the total amount of the composition.

< lubricating oil composition >

The base number of the lubricating oil composition of the present invention is 15 to 125mgKOH/g, preferably 20mgKOH/g or more, more preferably 30mgKOH/g or more, still more preferably 40mgKOH/g or more, and further preferably 120mgKOH/g or less, more preferably 105mgKOH/g or less, and still more preferably 100mgKOH/g or less.

When the base number of the lubricating oil composition is less than 15mgKOH/g, the detergency may be insufficient, and when the base number of the lubricating oil composition exceeds 125mgKOH/g, an excessive alkali component may be accumulated in the piston to inhibit the formation of an oil film, and bore wear (bore corrosion) or scuffing may occur, which is not preferable.

The lubricating oil composition of the present invention has a kinematic viscosity at 100 ℃ of 10 to 30mm²S, preferably 12mm²A length of at least s, more preferably 12.5mm²At least s, more preferably 16.3mm²More than s, particularly preferably 18.0mm²More than s, preferably 27mm²(ii) less than s, more preferably 26.1mm²A thickness of 21.9mm or less, preferably²A thickness of 21.0mm or less, particularly preferably²The ratio of the water to the water is less than s.

The kinematic viscosity at 100 ℃ of the lubricating oil composition is less than 10mm²In the case of/s, the oil film forming property is not sufficient, and the piston ring and the cylinder liner may be sintered, which is not preferable. Further, the kinematic viscosity at 100 ℃ of the lubricating oil composition exceeds 30mm²In the case of/s, the high viscosity may deteriorate the startability, which is not preferable.

In a second embodiment of the lubricating oil composition of the present invention, the Ph value represented by the following numerical formula (1) is 20 × 10^－3Hereinafter, it is preferable that19×10^－3Hereinafter, more preferably 18 × 10^－3The following. When the Ph is not more than the upper limit, the anti-emulsification property can be improved, and the scum production in the scrubber can be suppressed.

Ph value ═ C_Ca×2/(r_M×40.08)…(1)

(in the formula (1), C_CaRepresents the calcium content (% by mass) from the (A1) component, r_MThe metal ratio of the (A1) component is shown. )

The calcium content (% by mass) derived from the (a1) component means a value in which the calcium content derived from the Ca phenate-based detergent (a1) component in the lubricating oil composition of the present invention is represented by mass% based on the total amount of the lubricating oil composition. The metal ratio of the component (a1) as used herein is a value calculated from the following formula in the Ca phenate detergent as the component (a 1).

(A1) The metal ratio of component (a1) is the calcium content (% by mass) in the Ca phenolate based detergent component (a 1)/the calcium content (% by mass) of the soap base in the Ca phenolate based detergent component (a1)

< Cylinder lubrication method >

A cylinder lubricating method for a crosshead diesel engine equipped with a scrubber according to a second aspect of the present invention includes: (i) a step of operating a crosshead diesel engine equipped with a scrubber while supplying the lubricating oil composition according to the first aspect of the present invention to a cylinder of the crosshead diesel engine; and (ii) a step of purifying at least a part of the gas discharged from the cylinder in a scrubber.

Known devices can be used without limitation as a crosshead type diesel engine provided with a scrubber (see, for example, patent documents 1 to 5). The method for supplying the lubricating oil composition according to the first aspect of the present invention to the cylinder of a crosshead diesel engine is not particularly limited, and a method for supplying a lubricating oil to the cylinder, which is known in crosshead diesel engines, can be used. The scrubber may be an EGR scrubber, may be a scrubber in which gas passing through the scrubber is discharged to the environment without returning to the suction side, or may be a combination thereof. However, in view of the fact that the lubricating oil composition according to the first aspect of the present invention can advantageously exhibit an effect of improving the demulsification property, the scrubber is preferably a scrubber in which gas introduced into the scrubber is brought into contact with water and/or an alkaline aqueous solution to purify the gas. As the alkaline aqueous solution, for example, an aqueous solution in which a base such as an alkali metal hydroxide or an alkali metal carbonate is dissolved is preferably used, and in addition to this, seawater is preferably used.

Examples

The present invention will be described in more detail below based on examples and comparative examples. However, the present invention is not limited to these examples.

< examples 1 to 11, comparative examples 1 to 7 >

In a first embodiment of the lubricating oil composition, lubricating oil compositions having the compounding schemes shown in tables 1 and 2 were prepared, and a high-speed emulsification test was performed. The results are shown in tables 1 and 2. Wherein, in tables 1 and 2, the amount of the base oil is a content based on the total amount of the base oil, and the amount of the additive is a content based on the total amount of the composition.

(commercially available Cylinder oil)

Comprises the following components: 81% by mass of a mineral oil base oil, R in the above formula (1)¹Ca phenate-based detergent and Ca carbonate sulfonate-based detergent each having an alkyl group or alkenyl group having 12 carbon atoms (wherein a hydrocarbon group having 20, 22 or 24 carbon atoms is bonded to an aromatic six-membered ring), and R in the above formula (4)⁴Polybutenyl succinimide which is polybutenyl group, alkyl diphenylamine (the number of carbon atoms of the alkyl group is 4 and 8), alkylphenol, Si compound. The calcium content of the commercially available cylinder oil was 2.60% by mass in terms of the calcium content, based on the total amount of the commercially available cylinder oil. The nitrogen content of the commercially available cylinder oil was 0.03 mass% in terms of nitrogen content, based on the total amount of the commercially available cylinder oil.

(base oil)

Base oil 1: solvent refined base oil, 500N, kinematic viscosity at 100 ℃ of 10.8mm²(s) saturated component content 62% by mass

Base oil 2: solvent refined base oil, Bright Stock, kinematic viscosity at 100 deg.C of 31.8mm²(s) saturated component content 46% by mass

(Metal-based detergent)

Ca phenate salt: in the formula (1), A is a thioether group, x is 1-2, m is 1-2 Ca phenolate, the base number is 250mgKOH/g, the Ca content is 8.9 mass%, the metal ratio is 4.5, and the sulfur content is 3.5 mass%

Ca sulfonate: a base number of 400mgKOH/g, a Ca content of 15.5 mass%, a metal ratio of 20

(Nitrogen-containing ashless dispersant)

Nitrogen-containing ashless dispersant: in the above formula (4), R⁴Is polybutenyl succinimide, N is 5, N content is 1.1 wt%, Mw is 2490, weight average molecular weight Mw of polybutenyl moiety is 1000

(anti-emulsifier)

B-1: polypropylene glycol stearyl ether, Mw 1600

B-2: polypropylene glycol butyl Ether (NEWPOL LB-285, manufactured by Sanyo chemical industries Co., Ltd.), Mn 1170

B-3: polypropylene glycol butyl Ether (NEWPOL LB-1715, manufactured by Sanyo chemical industries Co., Ltd.), Mn 2390

B-4: oxyethylene-oxypropylene copolymer, Mw 4840

Sorbitan monooleate: HLB 4.3

< evaluation method >

(high speed emulsification test)

This experiment is a simulation experiment that simulates the oil-water separation process after agitation in a scrubber.

40g of an aqueous solution of sodium hydroxide (pH 12) and 10g of a sample oil were put into a 100ml measuring cup. After placing the cylinder on a homogenizer (POLYTRON PT 10-35 manufactured by KINEMATICA, starter shaft PT36/4K) and stirring at 15,000rpm for 5 minutes, the homogenizer was lifted up above the measuring cup and left to stand for 5 minutes, and the moisture, oil and emulsion adhering to the homogenizer were recovered in the measuring cup. The measuring cup after the test was left standing at room temperature for 1 week, and the separation performance was judged from the amount of separated oil as follows.

Oil amount separated 10 ml: the score of the order of 3 is given,

the separated oil amount is more than 7.5ml and less than 10 ml: the score was 2.5 and the score was 2.5,

the separated oil amount is more than 5ml and less than 7.5 ml: the score of the order of 2 is given,

separating oil with volume of more than 1ml and less than 5 ml: the score is 1 and the score is 1,

the separated oil amount is less than 1 ml: score 0

A score of 2 or more was regarded as passed, and a score of 1 or less was regarded as failed.

< evaluation result >

The lubricating oil compositions of examples 1 to 11 exhibited good separation performance in the high speed emulsification test (Table 1). The compositions of comparative example 1 and comparative examples 5 to 7, which did not contain the component (B), the composition of comparative example 2, which contained the component (B) in an amount of less than 0.02 mass%, and the compositions of comparative examples 3 to 4, which contained a surfactant having no anti-emulsification effect in place of the component (B), were all rated as 0 (failed) in the high-speed emulsification test, and had poor separation performance (Table 2). Among them, the composition of comparative example 1 (i.e., a commercially available cylinder oil itself) having a score of 0 in the high-speed emulsification test was used as a cylinder lubricating oil, and when a crosshead diesel engine was operated and the exhaust gas was cleaned with a scrubber, it was found that scum was generated in the scrubber.

[ Table 1]

[ Table 2]

< examples 12 to 26 and comparative examples 8 to 13 >

In the second embodiment of the lubricating oil composition of the present invention, lubricating oil compositions having blending ratios shown in tables 3 to 5 were prepared, and a high-speed emulsification test was performed in the same manner as described above. The results are shown in tables 3 to 5. In tables 3 to 5, the amount of the base oil is the content based on the total amount of the base oil, and the amount of the additive is the content based on the total amount of the composition.

(base oil)

((A1) component)

(A1) -1: in the formula (1), A is a thioether group, a Ca phenolate having x of 1 to 2 and m of 1 to 2, the base number is 250mgKOH/g, the Ca content is 8.9 mass%, the metal ratio is 4.5, and the sulfur content is 3.5 mass%

(A1) -2: in the formula (1), A is a thioether group, x is 1-3, m is 1-4 Ca phenolate, the base number is 150mgKOH/g, the Ca content is 5.4 mass%, the metal ratio is 2.7, and the sulfur content is 4.1 mass%

(A1) -3: in the formula (1), A is methylene, x is 1-3, m is 1-4 Ca phenolate, the base number is 70mgKOH/g, the Ca content is 2.5 mass%, and the metal ratio is 1.3

((A2) component)

(A2) -1: ca sulfonate with a base number of 400mgKOH/g, a Ca content of 15.5 mass%, a metal ratio of 20

(A2) -2: in the formula (2), M is calcium and R²An alkyl group derived from an alpha-olefin having 14 to 18 carbon atoms, a Ca salicylate having n of 1 to 2, a base number of 225mgKOH/g, a Ca content of 8.2 mass%, and a metal ratio of 3.1

(component (C-1'))

(C-1') -1: in the above formula (4), R⁴Polyisobutenyl succinimide of N-5, bis type, N content 1.1 mass%, Mw-2490, weight average molecular weight Mw of the polybutenyl moiety being 1000

(C-1') -2: in the above formula (3), R³Is polybutenyl succinimide of N-4 type, N content is 2.0 wt%, and Mw is 1000

< evaluation result >

The lubricating oil compositions of examples 12 to 26 exhibited good separation performance in the high speed emulsification test (tables 1 and 2). The lubricating oil compositions of examples 24 to 26 exhibited satisfactory demulsibility even when the component (C) functioning as a dispersant was contained in an amount of 0.015 mass% or less based on the total amount of the composition in terms of the nitrogen component. Ph value of more than 20X 10^－3The compositions of comparative examples 8 to 10 were all rated as 0 (failed) in the high-speed emulsification test, and had poor separation performance. In the compositions of comparative examples 11 to 13 in which the content of the component (C) based on the total amount of the composition was more than 0.015 mass% in terms of nitrogen component, though the Ph value was 20X 10^－3However, the results were all rated as 0 (no good) in the high-speed emulsification test, and the separation performance was poor.

[ Table 3]

[ Table 4]

[ Table 5]

Claims

1. A cylinder lubricating oil composition for a crosshead diesel engine equipped with a scrubber, characterized by comprising:

comprising a base oil and (A) a metal-based detergent,

The lubricating oil composition contains (B) 0.02 to 5.0 mass% of an anti-emulsifier based on the total amount of the lubricating oil composition,

contains 0.2 mass% or less of (C) a nitrogen-containing ashless dispersant based on the total amount of the lubricating oil composition, or does not contain (C) a nitrogen-containing ashless dispersant,

the metal cleaner (A) is 1 or more than 2 selected from phenate cleaner, sulfonate cleaner and salicylate cleaner,

the component (B) is more than 1 polyether compound,

the number average molecular weight of the component (B) is 500 or more,

the lubricating oil composition is a full loss type lubricating oil.

2. The cylinder lubricating oil composition for a crosshead diesel engine equipped with a scrubber according to claim 1, wherein:

the number average molecular weight of the component (B) is 1170-5000.

3. The cylinder lubricating oil composition for a crosshead diesel engine equipped with a scrubber according to claim 1, wherein:

the metal-based detergent (A) is at least 1 calcium-based detergent selected from the group consisting of Ca phenate-based detergents, Ca sulfonate-based detergents and Ca salicylate-based detergents.

4. A cylinder lubricating oil composition for a crosshead diesel engine equipped with a scrubber according to any one of claims 1 to 3, characterized in that:

the metal cleaner (A) is Ca phenate.

5. A cylinder lubricating oil composition for a crosshead diesel engine equipped with a scrubber, characterized by comprising:

comprising a base oil and (A) a metal-based detergent,

The component (A) contains (A1) a Ca phenate detergent and (A2) a metal detergent other than the Ca phenate detergent,

without (C-1') a succinimide having at least one alkyl or alkenyl group in the molecule or a boronated derivative thereof,

the Ph value shown in the following formula (1) is 20X 10^－3In the following, the following description is given,

the lubricating oil composition is a full loss type lubricating oil,

ph value ═ C_Ca×2/(r_M×40.08)…(1)

In the formula (1), C_CaRepresents the calcium content in mass% from the component (A1)_MThe metal ratio of the component (a1) is represented, and the metal ratio of the component (a1) is calculated according to the following formula:

(A1) the metal ratio of component (a) is (a1) the calcium content (% by mass) in the Ca phenate based detergent component (a1) and the calcium content (% by mass) derived from the soap base in the Ca phenate based detergent component (a 1).

6. A cylinder lubricating oil composition for a crosshead diesel engine equipped with a scrubber, characterized by comprising:

comprising a base oil and (A) a metal-based detergent,

containing (C-1') succinimide having at least one alkyl group or alkenyl group in the molecule or its boronized derivative in an amount of more than 0 mass% and not more than 0.015 mass% based on the total amount of the composition,

the lubricating oil composition is a full loss type lubricating oil,

ph value ═ C_Ca×2/(r_M×40.08)…(1)

7. The cylinder lubricating oil composition for a crosshead diesel engine equipped with a scrubber according to claim 5 or 6, characterized in that:

the component (A2) is Ca sulfonate and/or Ca salicylate.

8. A method for lubricating a cylinder of a crosshead diesel engine equipped with a scrubber, comprising:

a step of operating a crosshead diesel engine equipped with a scrubber while supplying the lubricating oil composition according to any one of claims 1 to 7 to a cylinder of the crosshead diesel engine; and

a step of purifying at least a part of the gas discharged from the cylinder in the scrubber,

does not include a step of repeating the operation of purifying the lubricating oil composition and then lubricating the cylinder.

9. A method of lubricating a cylinder of a crosshead diesel engine equipped with a scrubber according to claim 8, characterized in that:

the purging in the scrubber comprises a step of contacting the gas introduced into the scrubber with water and/or an alkaline aqueous solution.